Converter for continuous current.



@mixed Sept. 10, 19712.

3 SHEETS-SHEET l.

plan View of a WILHELM ALHORN, or EEELIN, GERMANY.

CONYERTER FOR CONTINUOUS CURRENT.

Specication of Letters Patent.

Patented sept. 1o, 191' a Application led June 8, 1911. Serial No. 631,989.

To. all whom, t1/tay concern.'

Be it known that I, WlLHELM ALHOBN, student of engineering, a subject of the German lilmperor,and residing at 9 Wollinerstrasse, Berlin, Germany, have invented certain new and useful Improvements in Convertel-s for Continuous Current, of which the following is a speciiication.

4'llhis invention relates-to apparatus for transforming a continuous current from one voltage to another, and the object of my invention is to provide a'transformer in which a periodic change of the magnetic field '1S produced, causing a corresponding transfer of electric energy by induction between the primary and secondary coils without phys cal movement of the primary or secondary members My invention will be understood from the following description, in connection with the accompanying drawings, in which- Figure 1 is a diagrammatic representation of anv apparatus embodying my invention; Fig. 2 is a side elevation of the same; Fig. 3 is a diagram illustrating the relative position of the magnetic poles; Fig. 4 is a top modified form of my transformer, showing a different commutator construction from that of Fig. 1; Fig. 5 is a diagram illust-rating an arrangement of the coils and commutator connections to produce sparkless commutation; Fig. 6' is a longitudinal section showing an arrangement of the primary and secondary coils with respect to the magnetic core; and Fig. 7 is a plan View of a modified form of the cornmutator.

Referring to Fig. 1, the primary coils P and secondary coils S, of the transformer, are arranged in superposed relation upon a longitudinal magnetic core 22. These coils are wound continuously, the ends being connected respectively by the wires 16 and 17,

.each coil being divided into sections, as in a Gramme ring,` the sections of the primary being connected to the annularly arranged commutator segments 2, and the secondary sections to the segments 10, which are carried by the insulating circular base 1. The slip rings 7 and 8 are connected with a suitable source of current to be transformed,

and the secondary or transformed current is taken from the rings 7 and 9, through suit.

able connections 11, shown in Fig. 2. The brushes for conveying the current to the segments connected with the primary and 32, the sections being connected to cessi-ve segments in a right-hand direction, jt-hen the last section on the right, Pc, will be connected to the segment 2c. If there are '2" sections in the primary' and secondary secondary coil sections are carried by the rotary arm 8, whichis mounted upon a central shaft or arbor and is provided with n driving pulley, as shown in Fig. 2. The lower primary-coil brush 4, is connected With the brush 6 bearing upon the' ring 8, and the upper secondary-coil brush 12 is connected with the brush 13, bearing on the ring 9, whileboth the upper primary brush 4 and the lower Secondary brush 1.2 are con- 7 common to the primary and secondary hand section P* is connected to the segment the succoils, then there are n sections between the brush connections. Ilfhus, if at one instant, one brush 4 is connected with section Pb, the other brush 4, diametrically opposite, will be connected to thewire 16 connecting the lends of the coi-ls P .and Pc. 'In this position of the brushes, the north pole will be atithe center of the magnetic core and the ends will be of opposite. or south polarity, as indicated in Fig. 3. As in dynamo electric machines, the secondary coil or induced member must be connected to the brushes at the neutral magnetic points, corresponding to the oints I, II, 1n Fig. 3.. I have in icated is arrangement in Fig. 1, by

-connecting coil S* by wire 20 to, segment 10, `which is 90 from t e segment 2, connected lrimary coil P". As the arm 3, carrying t e brushes, is rotated rapidly over e commutator segments by a motor, thedirection of the current in the sections of the coil is successively reversed and the polarity ofvthe,core advances longito the corresponding -tvudinall' in consequence of which currents will be induced in thev secondary coil which are taken from the commutator through the brushes and slip rings as a continuous current, the voltadepending` upon the ratio of transformation between the primary and secondary coils. In all positions of the brushes, the coils connected to opposite-sides thereof have' opposing currents therein and produce consequent poles at the opposite pointu' of connection with the'v flowing 4 .nected to the brush 5 bearing on the ring brushes, just as in the opposite sides ot a Gramme ring armature.v It is evident that there is nel magnetic path for the return or" the lines or force from these poles.

In order to secure a high eiiiciency in transformer constructions, 1t is important that the magnetic flux should traverse' closed magnetic paths. For'. this purpose, I prefer to arrange the'iron core parts in the manner shown in Fig. ti, i.n"'which lateral branches 32 project from the central iron core and pass between the sections of the primary and secondary coils and connect with a com mon magnetic returnor yoke piece 33. It is evident that with this construction the return magnetic ilus passes successively through each of the branch magnetic paths 32 into the yoke, and that the lines of :torce always pass through closed magnetic aths. i Induction between the primary an secondary can only take place when the mag-l netism is advancing longitudinally. When the brushes are in intermediate position and short-circuit two coils,.the magnetism does .not advance and consequently no induction currents are produced. When, however, a coil section is under the brush, there will be no current ot' self-induction which will produce sparking as the TIIbrush'passes oit of one segment to the next. In order to eliminate this sparking, the coils may be divided into two equal parallel portions, as shown in Fig. 5L Each commutator segment eX- tends over one half, and the sections of the coil sections are connected alternately to seg ments which are separated by an interme-` In thls manner the brushy diate segment. C connects the coil portions alternately and cannot short-circuit a coil section. At the instant when a brush rests upon two adjacent segments, both coil portions are connected in parallel, as the opposite brush rests upon the two correspdnding segments upon the other side of the commutator. The sparking due to the reactance of the individual coil sections will thus be avoided. It is obvious that this arrangement may be used for both primary and secondary or only one member.

The only limit in the voltageror tensiony which may be produced with the use of my vas shown, separated by insulating disks 24.

LOE/8,064;

The brushes Abearing upon opposite sides of the commutator are provided with teeth, after the manner of a comb, which project between the disks and bear upon the suri former. The brushes which bear upon the commutators and slip rings for both high and low voltage are carried by yokes secured to the shaft ot the motor indicated at the ri ht-hand end ot the machine, the bearings flor the motor being supported in the yoke 30 attached to the casing. It the pri mary side ol the transformer is the high tension side, the motor -should be provided with a double set of windings, and after being started from the high tension side 'can be switched over to the low voltage side.

during normal operation. The wires c011- necting the commutator segments with the coil sections should be carefully insulated, andv are preferably carried through the interior of the cylinder. The high and low voltage external leads are connected to suit-v ablebinding posts or eontactsb29v upon either end of' the machine.

In Fig. a, above described, rI have shownthe brushes connected to the motor shaft in a manner to berotated about the commutators. It is preferable, however, by reason c tionary brushes, and I have, therefore, llustrated such an arrangement in Fig. 7. The brushes 37 are connected with the respective coil sections, and bear upon an insulating cylinder 34: in'which are embedded two diametrically disposed helical conductin bars 35, which are connected respectively with the slip rings 36. When the vcylinder 34, connected to the motor shaft, `is rotated, the pairs of opposite brushes 37, will be connected in succession lthrough the bars 35, and .rings 36, with the circuit terminals or leads, edecting the commutation of the currents in the transformer coil sections in the usual manner. i

' The several advantages of my continuous current transformer will be appreciated by engineers and by those skilled in the art from the above disclosure of the invention. It has the advantage of requiring no rotating masses and no rotatin coils. lIt is self regulating, requires practically no attendance, and possesses a great overload capacity. The small motor for driving the the commutator is opern speed and therefore does MAGE. i o" this transformer is very iapted not only for the :torage plants, but also for ion purposes.

ve described in detail the conillnstrated in the drawings for the of disclosing embodiments of my ion, l aware that changes may be Jherein Without departing from the a tion, and l desire to invithin the scope of my niprising closed primary each divided into secgnetic core Within said teral branches extending beas, a return magnetic piece i said branches, a commusaid Sect-ions, and means z substantially unitorui and `nee of the magnetic field core and within said comprising closed primary f cils each owvhich is comnmetrieal interrelated portions into equal number of secl rear magnetic core Within said branches extending ber ziens, a' connmitator having sewnents for said coils, the corres o the two coil portions or' secondary respectively bethe commutator segments that diametrieally opposite will connect the coil portions alternately in circuit, and means for producing a continuously advancing magnetic field along said core and within said coils.

3. A converter comprising closed primary and secondary members, each ofwhich is divided int-o sections and one of which is composed of duplex symmetrical interrelated vcoil portions, a commutator having sets of segments connected respectively to the sections of the primary and secondary members, the set of segments connected to the duplex member being connected alternately to tl e coil portions, and a brush support carrying a set of brushes adapted to contact successively with the segments of the duplex coil portions, 'whereby the coil p0rtions thereof are connected alternately in circuit, and another set of brushes adapted to simultaneously Contact with the segments of the other member.

4. A converter comprising closed primary and secondary members concentrically arranged and extending longitudinally, each of which is divided into sections, a magnetic core extending longitudinally through said members, a commutator having segments connected to said sections, said commutator having Contact portions exnding spirally along the periphery of the support, and means cooperating with said segments for producing a continuously advancing magnetic field along said longitudinal core and within said coils.

In testimony whereof I hereto affix my signature in presence of two Witnesses.

lNlLl-IELM ALHORN.

Witnesses lVoLnnrvrAR HAUPT, HENRY HASPER. 

